It is known in the art to coat polyester substrates with phenol-blocked aromatic polyisocyanates from a single dip adhesive solution which also contains a polyepoxide and a rubber latex -- U.S. Pat. No. 3,234,067. The present invention produces an adhesive of this type, by a simplified procedure. The adhesive differs from that of the U.S. Pat. No. 3,234,067 in that somewhat better adhesion is obtained. Chemically the products differ in that the dip compositions of the present invention require the presence of alkali metal hydroxide, while the compositions of U.S. Pat. No. 3,234,067 exclude the presence of excess caustic.